In view of labor saving, resource saving and energy saving, a room-temperature rapid-curing adhesive composition is used as adhesives for bonding at room temperature and in a short time. Conventionally, as a room-temperature rapid-curing adhesive composition, a two-component rapid-curing epoxy adhesive composition, an anaerobic adhesive composition, an instantaneous adhesive composition and a second-generation acrylic adhesive composition (SGA) have been known.
The two-component rapid-curing epoxy adhesive is used by measuring and mixing a main agent and a curing agent, coating the mixture of the main agent and the curing agent on an adherend, and cures by a reaction of the main agent and the curing agent. However, the two-component rapid-curing epoxy adhesive is required to have higher peel strength and impact strength.
The anaerobic adhesive cures by pressuring the adhesive composition between adherends and blocking air. However, the anaerobic adhesive composition is required to cure even if a part of the adhesive composition contacts with air when a part of the adhesive composition protruded from the adherends during pressuring. Also, it is required that the adhesive composition cures even when a clearance between adherends is large.
The instantaneous adhesive usually contains a cyanoacrylate as a main component and is excellent in workability. However, higher peel strength and impact strength are required.
Although SGA is a two-component acrylic adhesive, it does not require precise measuring of two agents. Even if measuring or mixing is incomplete, the adhesive cures at room temperature for several minutes to several tens of minutes by just contacting two agents. It is used in a wide range of fields from the electric/electronic parts field to the civil engineering and construction field, since it has excellent workability, high peeling strength and impact strength, and good curing characteristics of the protruded part. Recently, SGA having less odor has been developed, and it can work even in places having only inadequate ventilation equipment.
Among various required characteristics, a characteristic under a low temperature environment is required, the adhesive cured product is also exposed to an environment below freezing point.
Under low temperature conditions, the adhesive cured product may become fragile, the adhesive strength may lower, and peeling may occur.